Create the database

The API stores links, click events and collections in PostgreSQL. You will use Amazon RDS, a managed database: AWS handles patching, backups and the operating system. The instance goes in the private subnets with public access turned off.

Create the subnet group#

RDS needs to know which subnets it may use. A DB subnet group is that list, and it must cover at least two Availability Zones.

Create the database#

aws rds describe-db-instances --region ap-south-1 --db-instance-identifier shortlink-db \
  --query 'DBInstances[0].{status:DBInstanceStatus,endpoint:Endpoint.Address,public:PubliclyAccessible,db:DBName,class:DBInstanceClass,storageGiB:AllocatedStorage}' \
  --output table

Two facts worth knowing#

• TLS is required. Recent PostgreSQL versions on RDS reject unencrypted connections. That is why the API's environment file sets DB_SSL=true, which makes the pg library connect over TLS.
• Always trust the console for the hostname. A stale hostname copied from an old note is the most common reason the API cannot reach the database. If you ever recreate the database, the endpoint changes, so update the API environment file. The troubleshooting chapter shows how to compare the two.

Next: IAM role for the server.